[aerohead]

NASA maintains a permanent presence at Edwards Air Force Base' Dryden Research Center.
While I was there, the Arab Oil Embargo of October, 1973 struck. Gasoline price doubled overnight. Gas rationing was instituted, and by 1974, a US National, 55-MPH Speed Limit was introduced, which stood for 20-years.
The US Department of Energy was created, and NASA was given funds to investigate a Cd 0.25 Semi-trailer and Cd 0.25 full-sized van.
They succeeded in both, and in 1980, the SAE Congress published their results.
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NASA's truck cab-to-trailer face gap-filler contributed a 17%, incremental, crosswind-averaged drag reduction. Part of their 'kit' to bring a Cd 0.717 semi down to Cd 0.25.
Tesla is one of the few corporations to incorporate this feature on their original Tesla Semi.
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This has been 'off-the-shelf' technology since 1980. Something the RV Industry has been blind to, for reasons unknown to me.
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1) Adding the 'Shorty' increased the Ioniq 5, combination to an estimated Cd 0.3349, from Cd 0.29.
2) Adding the gap-filler would yield an estimated Cd 0.2769.
3) Loosing the Shorty's fenders and cleaning up the details would yield an estimated Cd 0.1423.
4) Ditch the shorty, and do a optimized trailer and you're looking at Cd 0.12, 172.5 Wh /mile, & 195-mpg-e at 55-mph, and 448.6-miles range, on 77.4-kWh.
You gain 138.6 miles of range just by changing the shape.
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A couple, on an out-of-town camping trip, would not only experience a zero hit to 'fuel economy,' they'd actually be 'paid' to drive the rig, in non-taxable income.
They'd have a 'Transformer' pop-up camper, which could remain at the campsite, while the tow vehicle was used for local sight-seeing and so forth.
Opportunity charging at a 240-V, pull-though campsite would pay for the return trip home. No stops for recharging.